Elevator leveling system



Patented Jan. 21, 1947 2,414,562 ELEVATOR LEVELING SYSTEM Danilc Santini, Tenafly, N. 3., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application June 9, 1945, Serial No. 598,477

Claims. 1

My' invention relates to elevator control systerns "and 'more particularly to systems of this character which provide for leveling a car to a floor when it overruns or underruns that floor.

- One object of the invention is to provide for accurately leveling a car, when it overruns or underruns a floor, at a predetermined satisfactory speed and stopping it level with the floor so that a second leveling operation will not be necessary.

Another object is to provide the hoisting motor of an-elevator car with sufficient torque to set the car in motion in a leveling operation, but, once the motion is produced, to reduce the torque to a value sufficient to continue the movement of the car at the desired speed for leveling.

A further object is to prevent excessive speeds in leveling operations of the car and thereby prevent the necessity of additional leveling.

A further object is to provide for promptly restarting a car in case it should stall during a leveling 7 operation. v

A still further object is to provide for so controlling the brake during leveling operations as to cause it to softly and smoothly stop the car without any roughness in operation.

a For a better understanding of my invention, reference may be had to the accompanying drawings; in which:

Figure l is a diagrammatic representation, in what is known as the straight 1ine style, of an elevator system embodying my invention;

1A is a key representation of the relays embodied in Fig. l with their coils and. contact members disposed in horizontal alignment with their positions in the straight line circuit so that their locations therein may be readily determined;

Fig. 2 is an enlarged view of the inductor relay mounted on the top of the car for stopping it at the floor level; and

Fig. 3 presents a modified form of the circuit for the inductor relay Q.

;The following relays are included in the drawingsz U= up' direction switch VA=auxiliary low speed responsive relay Y=predetermined high speed responsive relay YA=auxiliary high speed responsive relay L=leveling relay fi9=door relay HGT-:noninterference time relay 5R=call registering relay 4R=ca1l registering relay 3R=call registering relay 2R:call registering relay lR=call registering relay l l=accelerating contactor i 2 :accelerating contactor i3=acceleratine contactor l4=accelerating contactor l lT=time relay for accelerating contactor I2T=time relay for accelerating contactor |3T=tirne relay ioraccelerating contactor l4T=time relay for accelerating contactor I2A=holding relay for the accelerating contactor I 3A=ho1ding relay for the accelerating contactor I4A=h01ding relay for the accelerating contactor Referring more particularly to the drawings, 1 have illustrated an elevator car C as supported by a cable l5 which passes over a hoisting drum I6 to a suitable counterweight II. The car is illustrated for use in connection with five floors, but it may be used for any desired number of floors.

The hoisting drum is mounted on a shaft l8 driven by an electric motor 2|. A suitable gear reducing mechanism 20 connects the shaft I8 with the motor 2| to secure an appropriate speed for the car when the motor is in operation. The hoisting motor 2| is illustrated as a three-phase single. speed alternating current motor comprising a rotor Zia and stator windings 23, 24, and 25 disposed to be connected to a suitable alternating current supply of energy represented by the conductors I, II and III for operating the car at a normal high speed of approximately one hundred feet per minute, although it may be designed for other speeds where desired,

An electromechanical brake B is provided for engaging a brake drum BD on the shaft I8 for stopping and holding the car at the floor landings. The brake may be the usual electromagnetic relay type of brake such as is provided with an electromagnetic coil BI and a brake applying spring B2,

A high discharge resistor Rl3, a low discharge resistor R, a series resistor Rl8 and a plurality of checking resistors RM, R15 and R16 are disposed in the circuit for the brake coil.

The high discharge resistor BB is permanently 3 connected in shunt relation to the brake coil to permit a rapid flux decay when the brake coil is disconnected from its source of energy.

The low discharge resistor RH is controlled by contacts of the car running relay M and the leveling relay L to be inserted in shunt with the brake coil when it is being deenergized during leveling operations to keep the brake from being.

too rough.

The series resistor RIB is controlled by back contacts on the leveling relay L to insure full energization of the brake coil while the car is running at high speed and also to cut down the current so it will not over-heat The checking resistors RIS'andRIE are controlled by a brake operated switch BK to insure the brake picking up enough and quickly soa leveling operation can start without delay when the car in answering a stop call stops short of or beyond the floor. The switch BK is disposed to be opened by the brake when it is partially picked. up.to insert the resistors RH: and RIG so that-the brake will be just: on the verge of setting again.

The resistor R14, and also the resistor Rl at times, is connectedfor control by a, pair OfCOntacts YAI to insert additional resistance in the brake circuit to partially apply the brake to prevent excessive leveling speedsduringleveling operations, as will be hereinafter described.

A simple push-button" system is provided for operating the motor to-move the car andit includes a plurality of pushbuttons, one for each floor landing, disposed inthe car for operation by a. car attendant or passenger. When one of the push buttons is-pressed, the carwill, after its door is closed, move to and stop at the floor of the operated'button. The push;v buttons are given the reference numerals IF, 2F, 3F, 4F and SP for the respective floors. 7

Associated with each push button is a call-registering-relay which is electrically; connected to a circuit 21 for causing the car to move in the up direction or in the down direction in accordance with the direction the car must move in response to the operation of a floor button. I

In" order to renderthe circuit 21 effective-for the correct direction, a plurality of normallyclosed cam switches IS, IS, 38, 4S and 58 are electrically connected between the floor points in the circuit and mounted on a floor selector 28 in position to be operated by a selector arm 30.- The arm is operated in accordance with the movementsof the car past the floors by a screwth-readed shaft-3| which is connected by a speed reducing gear 29 to the hoisting motor shaft I8; The cam switches IS, etc., and the selector arm should be so designed that the switch for a floor will b'e'opened when the car approaches within such a distance to the floor that'it can be decelerated and stopped at the door. However, the inventionmay be applied to any push-button control system where the push button starts the car, the selector determineswhen it should be stopped and a car carried inductor relay stops it.

The energy for operating the call registering relays, the direction switches, the car running relay and the other control apparatus issecured from a'plurality of supply conductors L+ I, and Ll and L+2- and L2 which may be connected to any suitable energy source.

An up direction relay W anda down direction relay X" are connected to the respective ends of the circuit 21 for controlling an up direction switch U, a-down di-rection switch D and'thecar. running relay M-which are used-for connecting 4 the motor to the supply conductors I, II and III in accordance with the direction in which the car should move when a car button is pressed.

An inductor relay Q is provided for stopping the car when it arrives at a fioor for which a push button, such as 3F, has been operated. The incluster relay Q includes an electroresponsive or energization coil and core with down stopping contacts QDS and up stopping contacts QUS and is mounted on the car in position to be operated, when energized through contacts of the direction relays W and X for a stop, by the influence of inductor plates of magnetic material mounted on the walls of the hatchway. The plates include an up-direction plate UP and a down-direction plateDP mounted on the hatchway wall at each floor for opening the inductor relay stopping contacts when the car brings the inductor relay opposite the plates at a floor in making a stop thereat. The plates may be of such length that the stopping contacts will be opened when the car. is aboutv nine inches from the floor level so that it may de'celerate and drift in under the control of the brake to a stop at the floor. The brake shouldbe sodesigned as to permit the car to drift a. reasonable distance when it is applied while the car is running at its normal high speed.

The inductor relay is also provided with normally closed down leveling contacts QDL and normally closed up leveling contacts QUL, the operation and use of which will be described later herein.

Inductor'relays of this character are old and well known in the art, but further information regarding them may, if desired, be secured from the White and Hearn Patent No. 1,889,446, issued October 25, 1932.

The inductor relay Q is used for controlling an rip-stopping relay LU and a down-stopping relay Ll), which are normally energized to maintain closed contacts in the circuits of the up-direction switch U and the down-direction switch D, so that when'theinductor relay is energized and is movedopposite the inductor plates for a floor,

3 its contacts. are opened and thereby deenergize thev stopping relay for the direction of the car, and it, in turn, opens its contacts in the circuit of the corresponding direction switch and thereby ffects thestopping of the car.

Inorder to secure a desirable acceleration of the hoisting motor when the car starts, the stator windings 23, 24 and. 25 are provided with a plurality of. resistors RI through RIZ. In starting the car on a Iloor-to-floor run, these resistors are short-circuited in timed steps to secure a desirable acceleration of thecar.

A plurality of accelerating contactors ll, [2, l3 and are provided for controlling the shortcii'cuiting of these resistors and a plurality of relays HT, I2T, HT and MT which have a time delay on dropping out are provided for causing operation of the accelerating contactors in timed sequence. The time delay of the relays is made very short, say, a few tenths of a second, so that the accelerating action will be comparatively rapid.

A plurality of holding relays IZA, HA and I 4A are provided for maintainingthe contactors in an energized condition once they have been energized. The holding relays are set up by the contactors but are maintained by the running relay M and, when energized to hold a contactor, will remain energized until the power is cut off the motor.

The non-interference time delay relay NT is provided for insuring time for a complete stopping operation for the car before it starts on another floor run. It is connected to be energized when the car starts and to be deenergized when it begins to slow down for a stop. It has a dropout delay after being deenergized of sufiicient time to permit the car to level and also to permit opening of the car door before the car can restart on another trip. 7 i A door safety relay 40 is provided for Prevent in'goperation of the car while either the car door 4 l -or a hatchway door (not shown) remains open. The'door relay is controlled by a circuit which includes safety contacts 32 on each door which are closedonly when that door is firmly closed.

-In practicing my invention for leveling a car into a floor when it overruns or underruns that floor in making a stop thereat, I provide forcontrolling the hoisting motor by increasing its torque in timed steps until it overcomes the static friction of the car and its operating apparatus sufliciently to start the car and by then reducing the torque to a value just sufficient to keep the car moving at a slow leveling speed. It also includes means for partially applying the brake if the speed of the car during that leveling operation increases beyond-a predetermined value. The means I have provided for so controlling the/motor andthe brake during leveling operations comprises a leveling relay L, a pair of up leveling contacts QUL and a pair of down leveling contacts'QDL on the stopping inductor relay, a speed measuring generator or tachometer TG, a low speed responsive relay V, an auxiliary low speed relay VA, a predetermined high speed responsive relay Y, and an auxiliary high speed relay YA. I

The leveling relay L is provided for conditioning the control circuits to effect the leveling of thecar with a landing floor when the car is to stop thereat but underruns or overruns the floor level. The leveling relay L is so controlled by the call indicating relay 80, the car running relay M and the low speed relay V as to be energizedfor leveling purposes only after the car comes to rest on its first slow down movement into a floor. While the car is making a floor to floor run, the relay L remains unenergized. The back contacts of the relay V included in the circult of the relay L keep it from being energized until thecar comes to rest in making a stop from a floor to floor run. The tachometer TG is supplied for controlling the low-speed relay V and the high-speed relay Yand is provided with an armature TGA and a field winding TGF. The field Winding is connected across the supply conductors L+2 and L-2 by front contacts of the time-delay relay HIT and by back contacts of the direction relays W and X.

The armature TGA is fixed on one end of the hoisting drum shaft I8 so it will be rotated by the hoisting drum whenever the car moves. The circuits of the low-speed relay V and the predetermined high-speed relay Y are electrically connected .to the brushes of the armature TGA so that movement of the car may cause the tachometer TG to supply energy'to the relay V and also to the relay Y in accordance with the speed of the car. .However, both of the direction relays W and X have back contacts disposed in the circuits of the field winding TGF and the relays V and Y. to prevent the tachometer from supplying current to the relays V and Yexcept during slowdown and leveling operations.

6 overheating and change of calibration due to heat. 7

The relay V should be so selected and adjusted that it will be energized sufliciently for operation by the tachometer TG to close its contact members V3 and open its contacts VI and V2 whenever the car starts to move in a leveling operation; conversely, the relay V will open its contact members V3 and reclose its contact members VI and V2 when the car stops movement in a leveling operation and thereby reduces the speed of the tachometer to zero. Obviously, the relay and generator may be designed and connected for any other speeds than starting speed where desired.

A resistor R2! is disposed in the circuit of the relay V and controlled by its back contacts V2 so that it will be inserted in series with the relay V when the relay picks up to cause it to remain just on the verge of dropping out again. Thus, a small decrease in speed of the car will lower the-voltage of the tachometer TG and thereby cause the relay V to drop out.

A resistor R20 is also disposed in the circuit of the relay V and is controlled by the contacts L2 of the leveling relay L to prevent excessive currents to the coils V and Y when the car stops from a slow-down action.

The back contacts VI of the relay V are used to prevent operation of the leveling relay L until after the car actually stops in answering a stop call at a floor. That is, the leveling can not start until after the car actually slows down and comes to rest in answering a, call at a floor.

The front contacts V3 are used for energizing the auxiliary slow-speed relay VA which, in turn, is used for increasing the amount of resistance in the hoisting motor circuit after it has been decreased sulficiently to cause the hoisting motor to overcome the static friction of the car and start it in motion, for the purpose of preventing an excessive increase in the speed of the car as the speed builds up to the desired leveling speed after the car starts during the leveling operation.

The relay VA effects this result by the use of its contacts VAI through VA8 in the circuits of the accelerating contactors and the timing relay contactors.

If the car should stall during a leveling operation, the stopping of the tachometer TF will cause relay V to drop out and it, in turn, will drop out the relay VA so that the time-sequence relays and contactors will again start to short-circuit the resistors in the hoisting motor field winding until the car is again started, whereupon the relay V will again operate to effect the re-insertion of the last resistor short-circuited to get the car started, and thereby maintain the leveling speed of the car at the desired value after it starts.

The predetermined high-speed relay Y should be so selected and adjusted that it will become energized sufiiciently by the tachometer TG to close its contacts Y2 and open its contacts Yl whenever the car exceeds the predetermined speed selected as desirable for leveling operations. The contacts Yl are used for inserting the resistor B24 in circuit with the relay Y, when the relay picks up, to cause it to remain just on the verge of dropping out again, so that a small decrease in the speed of the car in lowering the voltage of the tachometer TG will cause relay Y to drop out.

The front contacts Y2 are used for energizing the auxiliary high-speed relay YA which is provided with back contacts YAI for inserting the This prevents resistors RM and R15 in the circuit of the brake coil Hi to, reduce the strength of that coil and thus cause partial application of the brake if the .car should exceed th selected desirable leveling speed. Thus, if the levelin speed becomes excessive because of an'overhaulin load, the, relay Y picks up and decreases the energization of the brake coil to partially apply the brake and thus decrease the leveling speed.

The up levelingcontacts 'QUL provided in the inductor relay Q are so disposed'on the relay that they will, when the relay is energized,'open when they are at the plate DP butclose whenever the car drops approximately one-half inch below the floor level and thus moves them below the lower end .of the down plate DP. Thus the contacts QUL provide part of the means for leveling the car upwardly when it is slightly below the floor. The down leveling contacts QDL are so disposed on the inductor relay Q that they will, when the relay is energized, open when they-are at the plate UP, close whenever the car moves approximately one-half inch .abovethe level of the floor and moves :them above the upper end of the plate UP. Thus the contacts QDL provide part of the means for leveling the car downwardly.

When either pair of contacts QUL, or QDL is closed, it will energize the stopping relay for the corresponding direction to close contacts in the circuit of the direction switch for the corresponding direction and thus start the car. As soon as the car moves to its correct position with reference to the floor, the contacts QUL and QDL are opened to deenergize the relaysLU and LD and therebyopen the circuits for the up and the down direction switches to stop the-car and prevent its further movement.

The leveling relay L .-is provided with contacts LIO and Lil whicharedisposed in parallel with the stopping contacts QUS and QDS to prevent them from having anyefiect on theoperation of thecar during leveling operations.

It is believed that the invention maybe more readily understood from the following assumed operation of the apparatus.

It will be assumed that the car is standing at the lower floor, and that a passenger enters it, closes its doors and presses the third floor button to cause the car to move, up to the third floor.

Inasmuch as the car has been standing at the lower floor and the timing relay 1 T has timed out, the inductor relay Q is in a deenergized condition and, therefore, the contacts QUS, QUL, QDS and-QDL are closed so-that' theupstopping relay LU is energized by L-H, QUS, QUL, LU, L l, and the down stopping relay LD is energized by-L-H QDS, QDL, LD, L- I. The energized relays LU and LD have closed their contacts LUI and LD2 and Ll")! and LUZ .in the circuits of the up switch U and the down switch D- so that these switches are in condition to be energized for starting the car in either .direction whenever the car button is operated and the doors are closed. Also, the leveling relay L and the timing relays IIT, IZT, I-3Tand .MI-are in energized condition.

The closing of the doors energizes the door safety relay 40by thecircuit 11+2, 40, 32, L-2. The energized relay 40 closes its contacts 40I and 4fl2, thereby preparing the holdingcircuits of the up direction switch U and the down direction switch D for operation.

The operation of th third floor button 3F energizes the call registering relay .3R. and the up. di rection relay W byxthe,circuit; L+.l:,;3F, 3R, 4S, 58, 68, X5, W, L-t. (Inasmuchasthecar isstanding at the lower floor, the selector cam contacts IS are. Open, thereby preventing energization of the down direction relay X.) The energized relay 3R -'-closes its contacts 3Rl thereby providing a self-holding circuit for itself which will remain undisturbed until the movement of the car causes the floor selector arm to open the floor selector contact 4S.

The energized up direction relay W closes its contacts WI and W5 and opens its contacts W2, W3, W4 and W6. The opening of the contacts W2 will prevent energization of the field winding TGF, and the opening of the contacts W3 will prevent operation of the relays V and Y until the car starts to slow down for the next stop.

The opening of the contacts W4 will prevent energization of the inductor relay Q until the car arrives within stopping distance of the third floor. Theclosing of the contacts W5 further prepares thecircuit of the up direction switch U for operation. The opening of the contacts W6 interlocks the downdirection relay X to prevent its operation while the up'dircction relay W is energized.

The closing of the contacts WI energizes the call indicating relay by the circuit L+2, 80, TOT-I, Wt, L-2'. Theenergized relay 8D closes its contacts 80-2, 803 and 8i74 and opens its contacts -80-l. The opening of the contacts 80-! deenergizes the leveling relay L which thereupon opens its contacts L8 and L9 thus deenergizing the timing relays HT and IZT which will timeout when their time delay expires. The closing of the contacts 802 prepares a selfholding circuit for the relay 8,0. The closing of the contacts 86-4 has no eiiect, but the closing of the contacts til-ii completes a circuit for energizing the up direction switch U and the car running relay M by the circuit L+2, ill-l, 80-3, W5, .LUI, 'U, D4, M, .L-Z to cause the car to move upwardly to the third floor. The energized relay M operates its contacts to condition the various circuits for car operation. In doing this, it closes its contacts M11 and thereby energizes the time-delay relay TOT by the circuit. L+l, HIT, MI I, L- l. This relay will remain energized during the run of the car until the relay M is deenergized in-a stopping operation.

The energized up switch U closes its contact members-U1, U2, U3 and U4 and opens its contacts U5.v The closing of the contacts U4 provides a; self-.zholding-circuit for the switch U. The closing of the contacts U3 energizes the brake coil BI' .to release the Ebrake by the circuit L+I, U3, B4, Rtfl, L5, M6, L--l.

The closed contacts UI and U2 connect the field windings, 24 and 25 to the supply conductors I,LII andIlEIby the circuits I, M'I UL, '23, .RI, R2, R3, R4 to a point 35; II, M2, U2,24, R5, R5, R7, R8 to the point-35; and III, M3, 25, R9, RID, RI I, RIZ to the point 35.

Thehoistingzmotor is now energized for starting-the car'from the landing floor and it is now accelerated because the deenergized timing relays HT ,and- MT now time out and .close their back contacts II'ITJ and I2Tl, thereby energizing the contactor H by the circuit L+2, MIU, ll, IITI,

' VAQ, ;L2, and preparing the contactor [2 for operation. The energized'contactor II closes its contacts l l-l and l l2, thereby.shortecircuiting the resistors R4, R8 and R12 to-accelerate the hoistingmotor.

The energized relay ll also closes it :contacts "-4, thus energizing the ,contactor 12 to close its contacts. il2-l and 12- 2, thereby ishort-cin.

cuitingthe'resistors R3, R! and RI I, thus accelerating the hoisting motor still more. The energiz'ed contactor I2 also closes its contacts I2-4 and thereby energizes the holding relay I2A by L+I,"I2 4, I2A, M9, L-I, which closes its selfholding contacts I2AI and closes its contacts I2A2 to provide a holding circuit for the contactor II.

The energized contactor I2 also closes its contacts I2-5 to prepare the contactors I3 and I4 for operation and at the same time opens its .contacts I23 to deenergize the time delay relay I3T.

The relay I3T now times out and closes its back contacts I3TI and thereby energizes the contactor I3 by the circuit L+2, I25, I3, I3TI,VA1,

' L-2,to close its contacts I3I, I3-2, I3-3 and I3-5 and opens its contacts I34. The closing of the contacts I3l and I3-2 short-circuits the resistors R2, A6 and RIO, thereby accelerating the hoisting motor still further.

The closing of the contacts I35 prepares the contactor I4 for operation. The opening of the contacts I34 deenergizes the timing relay MT. The closing of the contacts I3-3 energizes the holding relay I3A by the circuit L+I, I33, I3A,

M9, L-I.

The energized relay I3A closes its self-holding contacts I3AI and also closes its contacts I3A2 to keep the contactor I2 in an energized condition.

The timing relay I4T now times out and closes its back contacts I4TI, thereby energizing the contactor I4 by the circuit L+2, I2--5, I4, I3-5, The energized rela I4 closes its contacts |4I and I4- 2 and thereby shortcircuits the resistors RI, R and R9 in the field of the hoisting motor, thus further accelerating the hoisting motor. The closing of the contacts t3 energizes'the holding relay MA by the circuit L+'I, |43, I4-A, M9, LI, The energized relay I4A closes its self-holding contacts I4AI and also closes its contacts I4A2 for maintaining the contactor I4 in its energized condition.

Thecar now accelerates to its full running speed and continues upwardly to the third floor. As it approaches the third floor at its normal running speed of approximately one hundred feet per minute, it causes thefioor selector arm to move along the selector switches and engage and open the switch 4S for stopping the car at the third The opening of the switch 45 restores the call registering relay 3R to its normal condition and deenergizes the Llp-dlIECtiOn relay W, which thereupon opens its contacts WI and \V5 and closes its contacts W2, W3, VM and W6. The closing of the contacts W4 energizes the inductor relay Q to effect the deenergization of the hoisting motor and the application of the brake when the car arrives at the up inductor plate for the third floor. The circuit through the relay Q extends L+2, W4, X4, 'IIIT3, Q, L2. The closing of the back contacts W2 energizes the tachometer field winding TGF by the circuit L+2, TGF, RI 9, 'IOTZ, W2, X2, L2. The closing of the contacts W3 closes the ring circuit 36 connected with the armature TGA of the tachometer for energizing the low speed relay V and the high speed relay Y. Inasmuch as the car is moving, the rotation of the hoisting shaft I8 rotates the armature TGA and sufiicient current flows through the relays V and Y to energize them.

The energization of the high speed relay Y closes" its contact members Y2, thus energizing the auxiliary high speed relay YA by the circuit L+2, YA, Y2, L2. The energized relay YA opens its contacts YAI, thereby inserting the resistors RI4 and RI5 in the brake circuit but this has no effect at this time because of the circuit 5 through L5.

The energization of the low speed relay V closes its contacts V3 and opens its contacts VI and V2. The opening of the contacts VI will prevent energization of the leveling relay L until the car actually stops for the third floor. The opening of the contacts V2 inserts the resistor R2I in circuit with the relay V to render it more sensitive to a decrease in the speed of the tachometer. The closing of the contacts V3 energizes the auxiliary low speed relay VA by the circuit L+2, VA, V3, L2. The energized relay VA closes its contacts VAI, VAZ, VAS'and' VA4, and opens its contacts VA5, VAS, VAT and VA8. The closing of the contacts VAi, VA2, VA3 and VA4 energizes the timing relays I IT through I4T to restore them to their normal energized condition ready for the next operation. The opening of the contacts VA5, VAG, VA! and VA8 opens the starting circuits for the contactors I I, I2, I3 and I4, but they still remain energized because of the contacts of the holding relays I2A, I3A and MA. Thus when the car running relay M is deenergized for the stop, the relays I2A, I 3A and MA will be deenergized so that the time relays, the contactors and the holding relays will be reset and ready for use in leveling.

As the car continues toward the third floor, it brings the inductor relay Q opposite the up plate UP and thereby opens the leveling contacts QDL which thereupon deenergize the down direction stopping relay LD, but, inasmuch as the relay LD is not efiective in any circuit, nothing happens. As the car continues still nearer to the third'floor, the up stopping contacts QUS come oppositethe lower end of the up inductor plate UP and are thereby opened to deenergize the up stopping relay LU, which, in turn, opens its contacts LUI and thereby deenergizes the up direction switch U and the car running relay M.

The deenergized up direction switch U opens its contacts UI and U2 and thereby'deenergizes the hoisting motor, It also opens its contacts U3 and thereby deenergizes the brake coil BI. thus applying the brake to stop and hold the car at the third floor. Inasmuch as the contacts U3,

D3, M6 and L4 are open, the setting of the brake will be controlled by the discharge resistor RI3.

It may be noted that the brake is so designed and the inductor plates are so located that the car will normally drift a distance of approximately nine inches in slowing down and stopping at a floor.

The deenergized relay M opens its contacts M5 and thereby deenergizes the call indicating relay 80, which closes its back contacts 80-I to prepare the leveling relay L for operation.

The opening of the contacts MII deenergizes the timing relay IDT, which will open after the expiration of approximately three seconds.

The opening of the contacts M9 deenergizes the holding relays I 2A, I3A and MA, which in turn open their contacts I2A2, I3A2 and I4A2 and thereby deenergize the contactors II, I2 and I3, and the deenergization of the contactor I2 opens its contacts l25 and thus deenergizes the contactor I4 so as to restore the accelerating resisters RI through IRIZ to the circuits of the hoisting motor field windings.

As the car drifts into the stop, its speed decreases to the predetermined high speed point set .11 for the relay Y, that relay drops out and'deenergizes the relay YA which in turn closes its back contacts YAI and thereby short-circuits the resistors RM and RI5 in the circuit of the brake coil BI to prepare the brake circuit for the next operation.

The car now stops its drift and stands still.

The car should stop level with the third floor landing, but it will be assumed that because of various operating conditions it overruns the third floor level so that the car floor is now above the third floor level.

The stopping of the car stops the armature TGA of the tachometer TG and it ceases to supply current to the low speed relay V, thereby deenergizing that relay.

The. deenergized relay V closes its contacts VI and V2 and opens its contacts V3. The closing of the contacts V2 shorts the resistor RZI in the circuit of relay V to make it easier for that relay to pick up when the tachometer starts.

The opening of the contacts V3- deenergizes the relay VA to open its contacts VAI, VAZ, VA3 and VA I in the circuits of the energized timing relays, I IT, IZT, I3T and MT to place their sequence of deenergization in the leveling operation under the control of the contacts M and the sequential operation of the contactors. At the same time, the relay VA closes its contacts VA5,

VAS, VA! and VA8 to prepare the contactors II,

L-'-2. Thereupon the relay L closes its contacts LI, L2, L3, L6 through LII and opens its contacts L5. The closed contacts LI prepare a selfholding circuit for the relay L until the car is ready to make its next trip. The closed contacts L2 and L3 short circuit the resistors R20 and R23 in the circuits of the relay V and Y which were used to protect the coils V and Y from. high voltage from thedevice TG when running at full speed.

The closing of the. contacts L4 completes a circuit, for the. low discharge resistor RII in the brake circuit to. keep the. brake from being too rough in leveling operations.

The. closing .of. the. contacts L8. and L9 reenergizes the timing relays [IT and IZT before they drop out under the-opening action of contactsVAI and VAL. The opening. of the contacts. L5. places the control of the brake. under the circuit in which the. resistors RM, RI 5 and RIG and contacts. YA]. and: BK are disposed, during the leveling period. Hence, all. the timing relays remain in operated condition and ready for operation if leveling is necessary, At the sam time it will be recalled that the contactors II, I2, I3 and- I 4 are in deenergized condition and that hence. the. resistors RI through RI2 are all effectively connected in the field winding circuit of the hoisting, motor.

Th closing-of the contacts LII]. and LII provides a; shunt circuit around .the stopping inductor contacts .QUS and QDS, and thereby render effective only the leveling inductor contacts QUL and QDL during the leveling period.

Theclosing of. the. contacts L6 and L1 close the. leveling connections for the up-direction switch U and. the. down-direction. switch D so that they may be. operatedwithout regard to the operation of the. direction relays; W or-X, the door'relay 40 or the call indicating relay 80. Now that the; leveling circuits to. the direction switches are completed by the leveling. relay- .L, the closed condition of the leveling contacts QDL because they are above the up plate UP will energize the down-direction stopping relay LD which, in turn. closes its contacts LD2 and thereby energizes the down-direction switch D and the car conditioning relay M by the circuit L+2, LI, LUZ, LD2, D, U5, M, L-Z.

The energized switch D closes its contacts DI and D2, thereby energizing the field windings of the hoisting motor and closes its contacts D3 to release the brake to move the car downwardly. We may assume that there is yet insufiictcnt motor torque to start the motor.

At the same time, the energized relay M opens its contacts M8, thereby deenergizing the timing relay I IT, which after a delay of a few tenths of a second closes its back contacts 9 ITi and thereby energizes the contactor II because the energized relay M has also closed its contacts Mill.

The energized relay II closes its contacts II-I and II2, thereby short-circuiting the resistors R4, R8 and RI 2 to increase the torque of the hoisting motor. The energized relay i I also opens its contacts II--3 and thereby deenergizes the timing relay i2T which after a few tenths of a second times out and closes its back contacts lZTI, thereby energizing the contactor I2 which in turn closes its contacts I2-I and I22 and thereby short-circuits the resistors R3, R! and RH to further increase the torque of the hoisting motor. We may assume that the motor still does not start. The energized contactor I2 also closes its contacts I2-4 thereby energizing the holding relay IZA to close its self-holding contacts IZAI and also to close its contacts IZAZ' for maintaining the contactor I I in its energized condition.

The energized contactor I2 also opens its contacts I 2-3 thus deenergizing the timing relay I3T which after a short time delay times out and closes its contacts I3Ti thereby energizing the contactor I3. The energized contactor I3 closes its contacts I3-I and I3-2, thereby short-circuiting the resistors R2, R6 and RIO to still further increase the torque of the hoisting motor.

' The energized relay I3 also closes its contacts of the car and its apparatus and thereby causes the car to start downwardly. The starting of the car rotates the armature TGA of the tachometer TG and thereby energizes the now very sensitive low speed relay V to open its contacts V! and V2 and close its contacts V3. The opening of the contacts VI does not affect the leveling relay L because it has provided. a self-holding circuit by means of. its contacts LI. The opening of the contacts V2 inserts. resistor R2I in. the circuit of the relay V as hereinbefore described. The closing of the contacts V3 energizes the auxiliary low speed relay VA which now closes its contacts VAI, VA2, VA3 and VA4 for reenergizing the timing relays IIT, I 2T, I3T and MT, and at. the same time opens its contacts VA5, VAE, VA! and VAB to place the contactor relays. II, I2, I 3' and I4 solely under the control of theholding relays 52A, [3A and MA.

Inasmuch as the contactor I4 had not yet 75 been energized at the time the car started, the

'13 holding relay .MA had not yet been energized to maintain the contactor 13 in an energized condition until the car conditioning relay M was deenergized at the stopping of the car. Consequently, when the tachometer starts and. energizes the low speed relay V which in turn energizes the auxiliary low speed relay VA and that relay opens its contacts VA'I, contactor i3 is .deenergized and thereby opens its contacts I3'land l3-2 thus returning the resistors R2, R6 and RIO to the field winding circuits of the hoisting motor and thereby reducing the torque usedfor starting the car to a desired value for operating at a desired leveling speed.

The foregoing operation illustrated how, in a leveling operation, sufficient torque is applied to the motor to overcome the static friction of the car and its apparatus, but as soon as that static friction, is overcome, the torque provided for the motor is reduced to a predetermined amount which'will give the car a very desirable leveling speed and not such a high leveling speed as -would be the case if the contactor l3 had not been withdrawn after having been placed in action to get the car started.

1 Occasionally because of load conditions the leveling speed may increase to an undesired value after the contactor I3 is retired in a leveling operation, In such a case the increased speed will cause the tachometer to increase the voltage applied to the high speed relay Y and thereby energizes that relay to open its contacts Yl to render itself more sensitive and to close its contact Y2 for energizing the auxiliary high speed relay YA. The energized relay YA thereupon opens its contacts YAI and inserts the resistors RM and RI5 in the circuit to the brake coil Bi. The insertion of the resistors RM and RIE in the brake coil circuit weakens the brake magnet and thereby permits the brake to be applied harder and increase the braking torque. This process continues with the result that the brake remains in the position where the necessary torque is developed to maintain the desired leveling speed. As soon as excessive landing speed is reduced to the desired value, the tachometer 'IG causes the relay Y to resume its unoperated con dition and thereby deenergize the auxiliary relay YA to close its contacts YAI and thus short-circuit the resistors RM and Rl5 in the brake coil circuit to hold the landing speed at the desired point.

As the car moves downwardly, it moves the downleveling contacts QDL down past the top of the up plate UP whereupon they open and thus deenergize the down'stopping relay LD, which in turn opens its contacts LDZ and thereby deenergizes the down-direction switch D and the running relay M. The deenergized relay D opens its contacts DI and D2 to disconnect the hoisting motor from its source of energy and opens its contacts D3 to deenergize the brake coil Bl to apply the brake. The open contacts MI 0 deenergize the contacts I I and I2 and the open contacts M9 deenergize the holding relays IZA and BA. As the brake is applied, the car stops and that stops the tachometer which fails to supply energy to the relay V, which therefore opens its contacts V3 and thus deenergizes the auxiliary relay VA which returns to its normal condition. Inasmuch as the contactors ll, l2, l3 and I4 are all deenergized and the leveling relay L is energized, the timing relays HT, I2T, I3T and MT are all energized and in condition for the next starting of the car.

It the car stalls for any reason during a leveling operation, the tachometer TG will cease operation at once and thereby deenergize the slow speed relay V, thus opening its contacts V3 and thereby deenergizing the relay VA to close its contacts VA! to again operate the relay l3 to decrease the resistance in the hoisting motor field until the car again starts.

It will be assumed at this time, that the car stops level with the third floor and that the passenger opens the car door and the associated hatch door to leave the car. The opening of the car door opens its door safety contact 32 and thereby deenergizes the door relay 40 to prevent any further operation of the car on another trip until the door is closed.

At this point the timing relay IOI times out and recloses its contacts IOTI to prepare the call indi-- cating relay for operation and opens its contacts IOTZ to prevent operation of the tachometer and opens its contacts 10T3 to prevent operation of the inductor relay Q while the car is standing in its unoperated condition at the third floor.

The system illustrated and described is well adapted for operation by the passengers who use the car, because the car will level only when it overruns or underruns a floor in making a stop and until the relay 'IBT times out. However, when an attendant is employed for operating the car, it is usually preferable to use a back contact of the door relay 40 (such as 40-4 in Fig. 3) for maintaining a closed circuit for the inductor relay while the car is standing at a floor so that the car can level at any time it moves away from the floor under the influence of cable stretch during its stop at a floor. At the end of the stop, when the door is closed to start the car on its next run, the door relay contacts 40-4 open to prevent op eration of the leveling means until the next stop.

From the foregoing operation it will be apparent that I have provided a simple and efiicient automatic leveling means for leveling a car into a floor when it overruns or underruns that floor, and that the leveling means provides for maintaining the leveling speed of the car at the predetermined desirable value and that this end is obtained by eliminating suflicient resistance from the field windings to get the car started and by then restoring some of the resistance to the field windings to keep the speed of the car down while it levels into the floor.

It will also be apparent that I have provided an additional means for partly applying the brake in cases where the leveling speed increases regardless of the additional resistance placed in the motor circuit after the motor receives sufficient torque to start the car Although I have illustrated and described only one specific embodiment of my invention, it is to be understood that any changes therein and modifications thereof may be made without departing from the spirit and scope of the invention.

I claim as my invention:

1. In an elevator control system for operating a car to serve a plurality of landings; a motor for the car; control means for causing the motor to start the car and stop it at the landings; leveling means operable in case the car underruns or overruns a landing in making a stop thereat for causing energization of the motor to move the car to the landing level; means responsive to operation of the leveling means for increasing the torque of the motor until it effects the starting of the car, means responsive to said starting of the car for of the motor.

15 reducing .ithe torque :of the motor, and :means responsive to a predeterminedhigh levelingspeed of th car for reducing the leveling .speed to a predetermined value.

2. In an elevator control system for operating a car'to serve'a'plurality of landings; a motorlfor the ."car; a brakacontrolzmeans for causing the motor to start the car and stop it"at thelandings; leveling means operable 'inacase the car underruns-or overruns 'alanding in making astop thereat for causing energization of the motor to move the car tofthe landing level; means operable in case the motor doesnotstart upon energization thereof for leveling foreausing increase in the torque of the .motor .until it moves the car, means responsive to movement of the carifor causing :'a :reduction in thetorque of the motor for 'operating'the car at a predetermined-speed during said leveling, andrmeans responsive to the roar exceeding .a predetermined speed xluring leveling for partially applying the brake to reduce the leveling speed.

3. In an elevator system :for operating a car to 'serve a plurality of floors, a motor for the car, :control meansfor causing'thezmotor to start the 'car'and stop it at'the floors, a leveling means responsiveto the car overrunning orunderrunning a' fioor'inim'aking a stop thereatgfor causing energization of the motor to level the car with that floor, a'plurality of switches associated with the motor, means'responsive to operation :of the leveling means for closing the switches intimed sequence to increase the torque of the motor in timed steps, a lowspeed 'device responsive .to a predetermined speed of the carin levelingoperati'on for preventing further operation of the timing devices, for opening the last .closed'switch to reduce the torque of the'motor, :andiresponsive to stalling'of the car for rec'losing said opened switch to again increase the torque of the rmotor until the car starts.

4. In an elevator system "for operating a car to servea plurality of floors, a motor "for the car, control means for causing'the motor to start the car and stopitiatzthefloorsya levelingmeans responsive -to -the car 'overrunning 'or underrunning a floor in making'a stop'thereat, for causing energization of the motorto level the car'with that floor, aplurality of switches associated with the motor, a plurality of timingdevicesresponsive to operation of the leveling means for closing the switches in timed 'sequence'to increase the torque of the motor in timed steps, and a low speed device responsive to a predetermined speed of the car in leveling operation for preventing further operationof the timing devices, and for opening the last closed switchtoreduce the torque In an elevator-system 'for operating a car to servea plurality of floors, a motor for the car, control means for causing the motor to start the car and stop it at the floors, a leveling'means responsive to the car overrunning or underrunning a floor in making a stop thereat, for causing energization of the motor to level the car with that floor, a plurality of switches associated with the motor,'means responsive to operation of the leveling means for closing the switches in timed sequence to increase the torque of the motor in timed steps, a low speed device responsive to a predetermined speed of the car in leveling operation for preventing further operation of the timing devices and'for opening the last closed switch to reduce the torque of the motor, an 'electromechanical brake forthe car,-said 'brake having 'two' parallelzcircuits, means responsive to operation of the levelingxmeans for opening one of the circuits during'leveling periods,and1means responsive to a predetermined high leveling speed for including a resistor in the other circuit to cause partial application of the brake to reduce the leveling speed.

6. In an elevator'system foroperating vacar to serve a plurality of floors, a motorfor the car, control means for causing the motor to start the car and stop it at the floors, an electromechanical brak for the .car, a leveling means responsive to the car overrunning or underrunning a floor in making a stop thereat, for causing ene'rgization of the motor to level the car 'with'that floor, a plurality of switches associated with the motor, a pluralityof timing devices responsive to operation of the leveling means for closing the switches in timed sequence to increase the torque of the motor in timed steps, a low speed device responsive to a predetermined speed of the'car in leveling operation for preventing further operationof the timing devices, and for opening'the last closed switch to :reduce the torque of'the motor, and a high speed device responsive to a predetermined high leveling speed of the car for partially applying the brake to reduce the'levling speed to a predetermined value.

'7. In an elevator system for operating a-car to serve a plurality of floors, a motorfor the car, control means for operating the motor to start the car and stop it at the floors, an electromechanical brake for the car,'a'leveling means for causing energization of the motor to level the car with a floor when it overruns or uhderruns that floor in making a stop thereat, a plurality of resistors connected in the circuit of the motor, a plurality of switches for short circuiting the resistors when the motor is to be accelerated, a plurality of timing devices for operating the switches in timed sequence, a "low speed device rendered effective by a stopping operation of the control means and responsive to the stopping of the car when it is making a stopping operation for rendering the leveling means effective andfor preparing the timing devices for operation, means responsive to operation of theleveling means for energizing the motor to move the car to a level with the floor at which the stop is being made and 'for starting the timing devices in operation to increase the torque of the motor, and means responsive to operation of the low speed device when the motor reaches a predetermined speed for stopping further operation of the timing devices and for causing the lastoperated switch to reinsert the resistor associated with it in the motor circuit to decrease the torque of the motor and thereby cause the car to level into the floor with a predetermined leveling speed.

8. In an elevator system for operating a car'to serve a plurality of floors, a motor for the car, control means for operating the motor to start the car and stop it at the floors, an electromechanical brake for the car, a leveling means for causing energization of the motor to level the car with a floor when it overruns or underruns that floor in making a stop thereat, a plurality of resistors connected in the circuit of the motor, a plurality of switches for short 'circuiting the resistors when the motor is to'be accelerated, a plurality of timing devices for operating the switches in timed sequence, a tachometer generator operable by movement of the car, means responsive to operation of thecon'trol means in a stopping operation for rendering the tachometer generator effective during stopping and leveling periods, a low speed device responsive to the stopping of the tachometer generator when the car is making a stopping operation for rendering the leveling means efiective and for preparing the timing devices for operation, means responsive to operation of the leveling means for energizing the motor to move the car to a level with the floor at which the stop is being made and for starting the timing devices in operation to increase the torque of the motor, and means responsive to operation of the low speed device when the motor reaches a predetermined speed for stopping further operation of the timing devices and for causing the last operated switch to reinsert the resistor associated with it in the motor circuit to decrease the torque of the motor and thereby cause the car to level into the floor with a predetermined leveling speed.

9. In an elevator system for operating a car to serve a plurality of floors, a motor for the car, control means for operating the motor to start the car and stop it at the floors, an electromechanical brake for the car, a leveling means for causing energization of the motor to level the car with a floor when it overruns or underruns that floor in making a stop thereat, a plurality of resistors connected in the circuit of the motor, a plurality of switches for short circuiting the resistors when the motor is to be accelerated, a plurality of timing devices for operating the switches in timed sequence, a plurality of holding devices, each of said holding devices being responsive to operation of a switch for maintaining the operation of the last previously operated switch, a tachometer generator operable by movement of the car, means responsive to operation of the control means in a stopping operation for rendering the tachometer generator effective during stopping and leveling periods, a low speed device responsive to the stopping of the tachometer generator when the car is making a stopping operation for rendering the leveling means effective and for preparing the timing devices for operation, means responsive to operation of the leveling means for energizing the motor to move the car to a level with the floor at which the stop is being made and for starting the timing devices in operation to increase the torque of the motor, and means responsive to operation of the low speed device when the motor reaches a predetermined speed for stopping further operation of the timing devices and for causing the last operated switch to reinsert the resistor associated with it in the motor circuit to decrease the torque of the motor and thereby cause the car to level into the floor with a predetermined leveling speed.

10. In an elevator system for operating a car to serve a plurality of floors, a motor for the car, control means for operating the motor to start the car and stop it at the floors, an electromechanical brake for the car, a leveling means for causing energization of the motor to level the car with a floor when it overruns or underruns that floor in making a stop thereat, a plurality of resistors connected in the circuit of the motor, a plurality of switches for short circuiting the resistors when the motor is to be accelerated, a plurality of timing devices for operating the switches in timed sequence, a tachometer generator operable by movement of the car, means responsive to operation of the control means in a stopping operation for rendering the tachometer generator effective during stopping and leveling'periods, a low speed device responsive to the stopping of the tachometer generator when the car is making a stopping operation for rendering the leveling means effective and for preparing the timing devices for operation, means responsive to operation of the leveling means for energizing the motor to move the car to a level with the flood at which the stop is being made and for starting the timing devices in operation to increase the torque of the motor, means responsive to operation of the low speed device when the motor reaches a predetermined speed for stopping further operation of the timing devices and for causing the last operated switch to reinsert the resistor associated with it in the motor circuit to decrease the torque of the motor and thereby cause the car to level into the floor with a predetermined leveling speed, and a high speed device responsive to a predetermined high speed of the tachometer generator during leveling operations for partially applying the brake to reduce the leveling speed of the car to a predetermined leveling speed.

DAN'ILO SANTINI. 

